On April 6, 1917, the Congress of the United States declared war against Germany. President Wilson had asked for the declaration on April 2, and had said that he wished to wage war to “make the world safe for democracy.”
The first small American units arrived in France in June 1917, and were in combat in October of that year. Eventually, the American Expeditionary Force numbered approximately 2 million men, with the total number of Americans drafted into service coming to 2.8 million. By the time of the Armistice in 1917, the United States had lost 116,516 men, with 204,002 wounded and 3,350 missing.
American entry into the First World War brought about revolutionary changes not only in training, organization, and command of the American military, but also in the relationship between the American citizen and their government. Massive propaganda programs, ranging from speeches to pamphlets, to suppression of anti-war sympathizers were instituted in a systematic, nationwide program.
For the first time, the law was used against citizens who disagreed. The Espionage Act of 1917, passed in June of that year, made it a crime to hinder the war effort or to give moral and material support to the Germans. It was amended in 1918 to make it a crime to criticize the government, the conduct of the war, or the military. In 1919, the Supreme Court found that the act, including the amendments that curtailed speech against the government, was constitutional. Although many of the 1918 amendments were repealed.
The AEF bolstered Allied forces, even though their arrival into the front line was delayed until they were properly trained and could enter combat as discreet units. General Pershing, their commander, had clashed with his counterparts in the British and French armies, who wished to intermix American units and individual soldiers with their formations. Pershing insisted on American control of American soldiers, a tradition that has persisted to this day.
American units would provide needed manpower in the battles to come in 1917 and 1918.